US3979666A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for evaluating properties of carbon fibers using capacitance sensing
Assignee: SUBJECT TO AGREEMENT RECITED SEE DOCUMENT FOR DETAILS
•
Filing: 1974-10-01
•
Granted: 1976-09-07
•
Expires: 1994-10-01
Abstract
Abstract A method and apparatus are provided for nondestructively evaluating physical properties of materials, and particularly semiconductive or electrically conductive fibers, e.g., carbonaceous fibrous materials containing at least about 90 per cent carbon by weight. The material is disposed in spaced relationship to a test electrode in an electrolytic solution and the physical property of the fiber is evaluated by evaluating the capacitance of the material. This capacitance evaluation may then be compared to the capacitance evaluation of a reference material having predetermined physical properties with the results of the comparison indicating the properties of the tested material. This indication may be utilized in the quality control of manufactured fibers by manual or automatic adjustment of the manufacturing process conditions. In fiber experimentation, this indication may be utilized to provide an evaluation of the effectiveness of an experimental process.
Inventors
- 👤 Alexander F. MacLean
- 👤 Ilmar L. Kalniv
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 03:32
CPC Classifications
G; G01; G01R; G01R27/00; G01R27/02; G01R27/26; G01R27/2605; G01N; G01N27/00; G01N27/02; G01N27/22
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
124 words
A method for controlling the manufacturing process of a carbonaceous fibrous material containing at least about 90 percent carbon by weight comprising the steps of: a. providing an electrolyte and a counter electrode in contact with the electrolyte; b. disposing the carbonaceous fibrous material being manufactured in contact with the electrolyte at a predetermined distance from the counter electrode; c. applying an electrical potential of known amplitude between the counter electrode and the carbonaceous fibrous material through a reference capacitor having a known value; d. sensing the amplitude of an output potential across the reference capacitor; e. evaluating a physical property of the carbonaceous fibrous material as a function of the sensed amplitude; and, f. controlling a process condition in response to the evaluation.
Claim 2
Independent Claim
124 words
A method for controlling the manufacturing process of a carbonaceous fibrous material containing at least about 90 percent carbon by weight comprising the steps of: a. providing an electrolyte and a counter electrode in contact with the electrolyte; b. disposing the carbonaceous fibrous material being manufactured in contact with the electrolyte at a predetermined distance from the counter electrode; c. applying an electrical potential of known amplitude between the counter electrode and the carbonaceous fibrous material through a reference capacitor having a known value; d. sensing the amplitude of an output potential across the reference capacitor; e. evaluating a physical property of the carbonaceous fibrous material as a function of the sensed amplitude; and, f. controlling a process condition in response to the evaluation.
Claim 3
Dependent Claim
17 words
The method of claim 1 wherein said carbonaceous fibrous material exhibits a predominantly graphitic x-ray diffraction pattern.
Claim 4
Dependent Claim
31 words
The method of claim 1 including the further step of wetting the carbonaceous fibrous material in a wetting solution prior to disposing the carbonaceous fibrous material in contact with the electrolyte.
Claim 5
Dependent Claim
45 words
The method of claim 3 including the steps of: a. disposing a reference electrode in contact with the electrolyte and spaced from the counter electrode and the carbonaceous fibrous material; and, b. applying a predetermined bias potential between the reference electrode and the counter electrode.
Claim 6
Dependent Claim
31 words
The method of claim 4 wherein the electrical potential is applied between the carbonaceous fibrous material and the counter electrode periodically at a rate of at least 10 pulses per minute.
Claim 7
Dependent Claim
49 words
The method of claim 1 including: a. dividing the sensed amplitude by a property of the carbonaceous fiber related to the fiber weight or size to obtain a normalized evaluation; and, b. comparing the normalized evaluation with a normalized evaluation of a reference fiber to obtain a relative evaluation.
Claim 8
Independent Claim
108 words
A method for controlling the manufacturing process of a carbonaceous fibrous material containing at least about 90 percent carbon by weight comprising the steps of: a. disposing a predetermined portion of the carbonaceous fibrous material being manufactured in spaced relation to an electrode; b. immersing the spaced carbonaceous fibrous material and electrode in an electrolytic solution to form an electrolytic cell having spaced electrodes; c. sensing the capacitance between the carbonaceous fibrous material and the electrode in the electrolytic cell; d. evaluating a physical property of the carbonaceous fibrous material as a function of the sensed capacitance; and, e. controlling a process condition in response to the evaluation.
Claim 9
Independent Claim
108 words
A method for controlling the manufacturing process of a carbonaceous fibrous material containing at least about 90 percent carbon by weight comprising the steps of: a. disposing a predetermined portion of the carbonaceous fibrous material being manufactured in spaced relation to an electrode; b. immersing the spaced carbonaceous fibrous material and electrode in an electrolytic solution to form an electrolytic cell having spaced electrodes; c. sensing the capacitance between the carbonaceous fibrous material and the electrode in the electrolytic cell; d. evaluating a physical property of the carbonaceous fibrous material as a function of the sensed capacitance; and, e. controlling a process condition in response to the evaluation.
Claim 10
Independent Claim
100 words
A method for controlling the manufacturing process of a carbonaceous fibrous material containing at least about 90 percent carbon by weight comprising the steps of: a. providing an elongated electrode; b. disposing the carbonaceous fibrous material being manufactured in a spaced relation to the electrode; c. applying an unidirectional current pulse to either one of the fibrous material and the electrode; d. sensing the current on the other of the carbonaceous fibrous material and the electrode; e. evaluating the current sensed as the surface characteristic of the fibrous material; and, f. controlling a process condition in response to the evaluation.
Claim 11
Independent Claim
100 words
A method for controlling the manufacturing process of a carbonaceous fibrous material containing at least about 90 percent carbon by weight comprising the steps of: a. providing an elongated electrode; b. disposing the carbonaceous fibrous material being manufactured in a spaced relation to the electrode; c. applying an unidirectional current pulse to either one of the fibrous material and the electrode; d. sensing the current on the other of the carbonaceous fibrous material and the electrode; e. evaluating the current sensed as the surface characteristic of the fibrous material; and, f. controlling a process condition in response to the evaluation.
Claim 12
Dependent Claim
17 words
The method of claim 8 wherein the carbonaceous fibrous material exhibits a predominantly graphitic x-ray diffraction pattern.
Claim 13
Independent Claim
108 words
A method for controlling the manufacturing process of a continuous length of a carbonaceous fibrous material containing at least about 90 percent carbon by weight comprising the steps of: a. providing an enclosure containing an electrolyte and a counter electrode in contact therewith; b. passing the continuous length of carbonaceous fibrous material being manufactured as a continuous test electrode in contact with the electrolyte present in said enclosure at a predetermined distance from the counter electrode; c. sensing the capacitance between the counter electrode and the fibrous material as the fibrous material passes through the electrolyte; and, d. controlling a process condition in response to the sensed capacitance.
Claim 14
Independent Claim
108 words
A method for controlling the manufacturing process of a continuous length of a carbonaceous fibrous material containing at least about 90 percent carbon by weight comprising the steps of: a. providing an enclosure containing an electrolyte and a counter electrode in contact therewith; b. passing the continuous length of carbonaceous fibrous material being manufactured as a continuous test electrode in contact with the electrolyte present in said enclosure at a predetermined distance from the counter electrode; c. sensing the capacitance between the counter electrode and the fibrous material as the fibrous material passes through the electrolyte; and, d. controlling a process condition in response to the sensed capacitance.
Claim 15
Dependent Claim
45 words
The method of claim 10 including the steps of: a. disposing a reference electrode in contact with the electrolyte and spaced from the counter electrode and the carbonaceous fibrous material; and, b. applying a predetermined bias potential between the reference electrode and the counter electrode.
Claim 16
Dependent Claim
30 words
The method of claim 11 including the further step of wetting the carbonaceous fibrous material in a wetting solution prior to disposing the fibrous material in contact with the electrolyte.
Claim 17
Dependent Claim
30 words
The method of claim 10 including the further step of wetting the carbonaceous fibrous material in a wetting solution prior to disposing the fibrous material in contact with the electrolyte.
Claim 18
Dependent Claim
89 words
Apparatus for controlling the manufacturing process of a fiber having an electrically conductive outer surface comprising: a test electrode disposed in spaced relation to the fiber being evaluated; an electrolyte intermediate the test electrode and the fiber and in contact with both the test electrode and the electrically conductive surface of the fiber being manufactured to thereby form an electrolytic cell; means for sensing the capacitance of the electrolytic cell to thereby evaluate a physical property of the fiber; and, controlling a process condition responsive to said sensing means.
Claim 19
Dependent Claim
89 words
Apparatus for controlling the manufacturing process of a fiber having an electrically conductive outer surface comprising: a test electrode disposed in spaced relation to the fiber being evaluated; an electrolyte intermediate the test electrode and the fiber and in contact with both the test electrode and the electrically conductive surface of the fiber being manufactured to thereby form an electrolytic cell; means for sensing the capacitance of the electrolytic cell to thereby evaluate a physical property of the fiber; and, controlling a process condition responsive to said sensing means.
Claim 20
Dependent Claim
65 words
The apparatus of claim 14 wherein said sensing means comprises: a reference capacitor; means for periodically applying an electrical potential through the reference capacitor to one of the test electrodes and the fiber; means for sensing the potential across the reference capacitor; and, means for providing an indication of the capacitance of the cell in response to the applied electrical potential and the sensed potential.
Claim 21
Dependent Claim
24 words
The apparatus of claim 15 including: a reference electrode; and, means for applying a bias potential between the reference electrode and the test electrode.
Claim 22
Dependent Claim
42 words
The apparatus of claim 15 wherein the fiber comprises a carbonaceous fibrous material containing at least 90 percent carbon by weight and means for moving the fibrous material through the electrolyte in contact therewith and in spaced relation to the test electrode.
Claim 23
Dependent Claim
19 words
The apparatus of claim 17 including a wetting solution for wetting the fibrous material prior to contacting the electrolyte.
Claim 24
Dependent Claim
156 words
Apparatus for controlling the manufacturing of a carbonaceous fibrous material containing at least about 90 percent carbon by weight comprising: a container provided with an electrolytic solution; a test electrode disposed within said container in contact with the electrolyte; means for disposing a carbonaceous fibrous material within said container in spaced relation to the test electrode, at least a portion of said carbonaceous fibrous material being in contact with the electrolyte; a reference capacitor; means for periodically applying an electrical potential through said reference capacitor to one of said test electrodes and said carbonaceous fibrous material; means for sensing one of the potential developed between said test electrode and said carbonaceous fibrous material and the potential across said reference capacitor; means for evaluating a surface property of the carbonaceous fibrous material in response to the magnitudes of the applied potential and the sensed potential; and, means for controlling a process condition responsive to said evaluating means.
Claim 25
Dependent Claim
156 words
Apparatus for controlling the manufacturing of a carbonaceous fibrous material containing at least about 90 percent carbon by weight comprising: a container provided with an electrolytic solution; a test electrode disposed within said container in contact with the electrolyte; means for disposing a carbonaceous fibrous material within said container in spaced relation to the test electrode, at least a portion of said carbonaceous fibrous material being in contact with the electrolyte; a reference capacitor; means for periodically applying an electrical potential through said reference capacitor to one of said test electrodes and said carbonaceous fibrous material; means for sensing one of the potential developed between said test electrode and said carbonaceous fibrous material and the potential across said reference capacitor; means for evaluating a surface property of the carbonaceous fibrous material in response to the magnitudes of the applied potential and the sensed potential; and, means for controlling a process condition responsive to said evaluating means.
Claim 26
Dependent Claim
33 words
The apparatus of claim 19 including: a reference electrode disposed within said container in contact with the electrolyte; and, means for applying a bias potential between said reference electrode and said test electrode.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-09-07 | 1980-03-08 | 1980-09-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-09-07 | 1984-03-08 | 1984-09-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-09-07 | 1988-03-08 | 1988-09-07 | $7700.00 | Window Closed / Lapsed |